Project 2.5i.1 - Hydrodynamics
at the whole-of-GBR scale

For detailed descriptions of the outputs for
this project for Year 4 (2009/2010) of the MTSRF Research
Programme, see the Annual Research
Plan.

An extension
task to Project 2.5i.1 is working to reveal the
underwater landscape of the northern Australian seabed by
developing a new and detailed 3D seabed map [Read more]

Hydrodynamic models simulate the advection
and mixing of water - processes fundamental in controlling the fate
and impact of freshwater, sediment, nutrients and pesticides
delivered from catchments in to the receiving waters of the Great
Barrier Reef (GBR) lagoon. We believe the modeling community is
currently in a position where it is feasible to develop a
whole-of-GBR hydrodynamic model that includes all of the important
factors affecting currents, mixing, temperature and salinity within
the GBR lagoon and exchanges with the adjacent Coral Sea.

This project aims to develop a
three-dimensional whole-of-GBR baroclinic hydrodynamic model (GBR
model) at a spatial resolution of approximately 1-2 km, with
accurate boundary forcing for offshore ocean boundaries provided by
a global, data-assimilating, eddy-resolving model. Such a
model will underpin the future development of other essential
components of a Large-Scale Water Quality (LSWQ) model, primarily
sediment dynamics and biogeochemical models, and provide a
capability to support the prediction and analysis of connectivity
and exchange of material, including larvae, throughout the GBR.

At this spatial resolution of ~1-2 km, a
critical challenge will be to deal with the range of spatial scales
encountered within the model domain, in particular the need to
resolve effects of reefs and reef passages at scales of less than
the model resolution. In order to meet this challenge, an important
part of this project will involve an investigation and assessment
of the necessity and suitability of sub-grid parameterisation
schemes within a model of this spatial resolution.

As a proof of concept for a full,
three-dimensional hydrodynamic model of the GBR, we will use the
model developed in this project to hindcast the circulation within
the GBR lagoon during the 2009 wet season, including prediction of
the trajectories and spatial distribution of major freshwater
inflows during this period.

Key objectives of this project are to:

Develop a three-dimensional whole-of-GBR baroclinic hydrodynamic
model, at a resolution capable of capturing the key oceanographic
processes impacting the GBR. This model is a necessary precursor to
the development of sediment dynamics and biogeochemical components
of a whole-of-GBR Water Quality Model;

Demonstrate proof of concept of a whole-of-GBR model through the
simulation of the circulation within the GBR lagoon during a
significant wet season, including prediction of the trajectories
and spatial distribution of major freshwater inflows during this
period; and

High-resolution depth model for the
Great Barrier Reef and Coral Sea

There is a critical lack of information about the location
and spatial extent of deep-water ecosystems and seabed habitats for
about a third of the Great Barrier Reef World Heritage Area
(GBRWHA) lying deeper than two hundred metres. In addition, most of
the inter-reefal seabed shallower than two hundred metres on the
GBR shelf, and in fact many of the 2,000+ coral reefs themselves,
have never been adequately mapped with modern echosounder
techniques. Therefore key seabed geomorphic features, such as shoal
habitats and submerged reefs, which help define the spatial
boundaries of deepwater ecosystems remain largely hidden from view
and outside of effective management. However, in recent years there
has been a vast increase in the amount of depth data obtained in
the GBR through a series of research vessel mapping expeditions.
Combined with the latest satellite remote sensing depth data and
light detection and ranging (LiDAR) results, this extension project
will develop a
new high-resolution depth model for the GBR and adjoining Coral
Sea (see graphic).

The spatial data tools and information provided by the project
will improve vital knowledge required for informing managers of the
GBRWHA. For example, managers require data on where the key
physiographic features in the deep GBR are. The managers also
require knowledge on how well the current zoning network protects
these seabed features and their associated biodiversity. In
addition, marine scientists require accurate and detailed depth
data for targeting seabed biodiversity sites and for planning
future research locations.

The project will determine the relief and spatial distribution
of key seafloor features through the development of a regional
~100m resolution digital elevation model (DEM), plus traditional
contour maps and shaded-relief images of the undersea landscape, or
seascape. The mapping outputs of the extension project will also
contribute to the concurrent e-Atlas project
to provide a web-delivered visualisation of the 3D seascape of the
GBRWHA.

Further Information

Dr David SouterGBR Program Research ManagerReef and Rainforest Research Centre LimitedTel: (07) 4781 6013david.souter@rrrc.org.au

Climate Change and the Great Barrier Reef

Climate Change and the Great Barrier Reef: A
Vulnerability Assessment is a peer-reviewed publication
compiled as a collaboration between the Great Barrier Reef Marine
Park Authority (GBRMPA) and over eighty leading climate and
tropical marine experts. The report includes a chapter by
MTSRF researchers based at the Australian Institute of Marine
Science (AIMS), Impacts of climate change on the
physical oceanography of the Great Barrier
Reef.

Major Project Outputs

The Annual Research Plans, or ARPs, outline the specific tasks,
products, budgets and staff for each research project within each
of the Research Themes and Programs of the MTSRF. The ARPs
also outline the key deliverables, or 'project
milestones' (e.g. major reports, journal articles,
communications products) to be achieved.

An ARP is developed for each operating year of the MTSRF
(2006-2010).

Details of this and previous years' outputs from this project
are included in each of the Annual Research
Plans.